Prospective evaluation of an Australian pertussis toxin IgG and IgA enzyme immunoassay

May, Meryta L., Doi, Suhail A., King, David, Evans, Jenny and Robson, Jennifer M. (2012) Prospective evaluation of an Australian pertussis toxin IgG and IgA enzyme immunoassay. Clinical and Vaccine Immunology, 19 2: 190-197. doi:10.1128/CVI.05430-11

Author May, Meryta L.
Doi, Suhail A.
King, David
Evans, Jenny
Robson, Jennifer M.
Title Prospective evaluation of an Australian pertussis toxin IgG and IgA enzyme immunoassay
Journal name Clinical and Vaccine Immunology   Check publisher's open access policy
ISSN 1556-6811
Publication date 2012-02-01
Year available 2011
Sub-type Article (original research)
DOI 10.1128/CVI.05430-11
Open Access Status DOI
Volume 19
Issue 2
Start page 190
End page 197
Total pages 8
Place of publication Washington, DC, United States
Publisher American Society for Microbiology
Language eng
Formatted abstract
Serological diagnosis of recent pertussis infection is an important part of both clinical assessment and epidemiological documentation of this disease. Standardization of serological testing and interpretation remains challenging despite international efforts to improve it. Currently, determining the anti-pertussis toxin (PT) IgG titer is recommended as the most accurate serological test in Europe and the United States, while Australia relies predominantly on measurement of Bordetella pertussis IgA antibody responses. Using B. pertussis PCR and the WHO clinical case definition as reference standards, the diagnostic utility of in-house anti-PT IgG and anti-PT IgA assays was evaluated prospectively in an Australian community-based cohort (n = 327). Patients provided up to four consecutive serum samples to document the kinetics of antibody response and decay. Previously validated cutoffs for positivity were converted to international units by using WHO-approved reference sera. At currently used cutoffs, both anti-PT IgG (>94 IU/ml) and anti-PT IgA (>20 IU/ml) assays had good specificity (80% [95% confidence interval {95% CI}, 68 to 88%] and 87% [95% CI, 77 to 94%]), but anti-PT IgG assay was consistently more sensitive than anti-PT IgA assay across a range of cutoffs (60 to 79% [95% CI, 53 to 84%] versus 41 to 62% [95% CI, 34 to 69%]). The combination of anti-PT IgG and anti-PT IgA assays performed no better than anti-PT IgG assay alone. The anti-PT IgA response in children under 12 years of age was poor. The accuracy of serology was optimal between 2 and 8 weeks after symptom onset. Cutoffs of >94 IU/ml for anti-PT IgG and >20 IU/ml for anti-PT IgA correlated well with recent pertussis infection and were consistent with recent recommendations from the EU Pertstrain group. Anti-PT IgG assay was superior to anti-PT IgA assay as the test of choice for the diagnosis of pertussis from a single sample.
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ
Additional Notes Published ahead of print 30 November 2011

Document type: Journal Article
Sub-type: Article (original research)
Collections: Discipline of General Practice Publications
Official 2012 Collection
School of Public Health Publications
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